The present disclosure relates generally to Advanced Process Control (“APC”) as applied to integrated circuit (“IC”) fabrication and, more particularly, to system and method for implementing a multi-resolution APC technique.
APC has become an essential component in semiconductor fabrication facilities (“fabs”) for enabling continued improvement of device yield and reliability at a reduced cost. Significant elements of APC include integrated metrology, fault detection and classification, and run-to-run control. APC aids in reducing process variation as well as production costs. A key requirement for effective APC is that metrology tools are available to measure key parameters within an acceptable time frame. Additionally, methods must be provided for analyzing and interpreting measurement data. In practice, APC requires rich in-line measurements because the manufacturing processes are usually subjected to disturbance and drift caused by a variety of sources. Traditionally, APC has been based on constant or near-constant time sequence data inputs; however, it is recognized that the complexity of processes, tools, and products results in multiple data sources that impact the control performance with different time frequency. In general, an APC controller operates with disturbances from both the wafer and chamber conditions. The disturbances, which may include, for example, metrology bias, calibration offsets, and the like, may be of different resolutions. Moreover, some of the disturbances are effective, while others are not.